The aim of this project is to determine whether removal of prefrontal cortex in infant rats produces functional recovery as it does in rhesus monkeys. Recent research by the applicant has shown that the functional subdivision of frontal cortex in the rat is very similar to that of the rhesus monkey, so I predict that the mechanisms of recovery fron frontal cortex destruction in the two species will also be similar. The behavioral tasks will be those which have produced double dissociation after removal of the two frontal subfields in the adult rat; namely, spatial reversals, delayed response, open field activity, and bar press extinction. If the mechanisms of recovery and conditions under which it occurs are the same for such diverse mammalian species as rats and monkeys, there is some assurance that the same might be true for humans with similar infant brain damage.